They contributed to the atmosphere of hysteria that swept the West Coast after the Pearl Harbor attack. Politicians and journalists urging the mass removal of Japanese Americans from the coast in early 1942 pointed to the Dies Committee's "findings" for support. Military officials used the findings to justify their decision to give the politicians what they were clamoring for.More here.
And in The Chronicle Review, Nelson Lichtenstein has a post on The Long History of Labor Bashing.